We have to use the chain rule's
\(f(x)=ln(17-x)\)
\(f[g(x)]=ln[g(x)]\)
therefore
\(f(u)=ln(u)\)
and
\(u=g(x)=17-x\)
them we have
\(f'(x)=f'(u)*g'(x)\)
\(f'(u)=\frac{1}{u}\)
\(g'(x)=-1\)
\(f'(x)=f'(u)*g'(x)\)
\(f'(x)=\frac{1}{u}*(-1)\)
\(f'(x)=-\frac{1}{u}\)
\(\boxed{\boxed{\therefore~f'(x)=-\frac{1}{17-x}}}\)
